Description
Mechanism of Action
Lidocaine is an amide type local anaesth. It stabilises the neuronal membrane and inhibits Na ion movements, which are necessary for conduction of impulses. In the heart, lidocaine reduces depolarisation of the ventricles during diastole and automaticity in the His-Purkinje system. Duration of action potential and effective refractory period are also reduced.
Onset: 45-90 sec (IV); approx 4 hr (transdermal); 20 sec to 5 min (ophth).
Duration: 10-20 min (IV); 5-30 min (ophth).
Absorption: Readily absorbed from the GI tract, mucous membranes, damaged skin, inj sites, including muscle; poor absorption through intact skin. Time to peak plasma concentration: 11 hr (transdermal) following application of 3 patches.
Distribution: Crosses the placenta, blood-brain barrier and enters breast milk. Protein-binding: 60-80% (α1-acid glycoprotein).
Metabolism: Undergoes rapid metabolism and approx 90% is dealkylated to monoethylglycinexylidide and glycinexylidide. First-pass metabolism is extensive.
Excretion: Via urine (<10% unchanged, approx 90% as metabolites). Elimination half-life (biphasic): Initial: 7-30 min; terminal: 1.5-2 hr.
MIMS Class
Anaesthetics – Local & General / Cardiac Drugs
ATC Classification
C01BB01 – lidocaine; Belongs to class Ib antiarrhythmics.;
N01BB02 – lidocaine; Belongs to the class of amides. Used as local anesthetics.;
S01HA07 – lidocaine; Belongs to the class of local ophthalmologic anesthetics.;
S02DA01 – lidocaine; Belongs to the class of analgesic and anesthetic agents used as otologicals.;
C05AD01 – lidocaine; Belongs to the class of local anesthetics. Used in the topical treatment of hemorrhoids and anal fissures.;
D04AB01 – lidocaine; Belongs to the class of topical anesthetics used in the treatment of pruritus.;
R02AD02 – lidocaine; Belongs to the class of local anesthetics used in throat preparations
